5.8S rRNA occurs in the large subunit of eucaryote ribosomes and is known to form specific associations with 28S rRNA, tRNAs, other 5.8S rRNAs, ribosomal proteins, and methyl transferases. Mammalian 5.8S rRNA is deprived of one of its 2'0 methyl groups in tumors, such as rat Novikoff ascites hepatoma. Hyporibosome function or general metabolism is not known. Structural studies of 5.8S rRNA, with and without the methyl group in question (Um14), will be conducted in this project and will provide the basis for understanding the interactions with 5.8S rRNA of the molecules listed above. The role of the 2'0 methylation may be discernable. Structural techniques of nulcear magnetic resonance (NMR), partial S1 nuclease digestion, native and denaturing gel electrophoresis, hyperchromic melting, sequencing, and Sanger fingerprint mapping will be used. Control studies include structural analysis of rat, yeast, chicken, and turtle 5.8S rRNAs, and examinaton of the mechanism of dimerization of rat 5.8S rRNA.